L9966 datasheet(41/122 Pages) STMICROELECTRONICS

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Result ADC channel x:

Sequencer results are fed into internal buffers then, before reading SQNCR_RESULT_x registers, a copy

command has to be issued.

Copy command can be issued by the two following options:

•

SPI reading access on SQNCR_RSLT_COPY_CMD register

•

SYNC pin trigger, provided that it is configured to be used for copy command operation, setting

SYNC_CMD_EN in SQNCR_CTRL register.

SPI reading access on SQNCR_RSLT_COPY_CMD register always issues a copy command even in case

SYNC_CMD_EN is set.

Buffering operation:

Figure 19. SEQUENCER flow example

GADG0801181136PS

The Figure 19 is an example of the sequencer using two EUs: EU1 has a sequence from CH1 to CH4, EU2

from CH5 to CH6. SYNC toggling has enabled the copy command. EU1 measures voltages (ADC1) while EU2

resistance (ADC2).

When EU1 completes its loop, interrupt is generated (see Section 9.3 Interrupt generation).

To read results, it is necessary to wait for the rising edge of SYNC filtered pulse, so that results are copied to

the SPI registers.

At readout, results are read with the “new result flag”, except for the CH6 result which is not available yet.

After readout, NEW_RESULT flag is cleared.

At next SYNC pulse, new results from EU1 are available. For EU2, only new result from CH6 is available,

CH5 is read with its NEW_RESULT flag cleared.

L9966 allows distinguishing whether data reported in SQNCR_RESULT_x register has been already read. In

case of voltage measurement bit SQNCR_RESULT_x[14] is set (clear on read bit). For resistance measurement,

instead, the whole content of the SQNCR_RESULT_x is reset once read.

Table 25 describes the copy command according to the availability of a new result and SPI readout operation

occurred before the copy command.

Table 25 is referenced to each sequencer line; the copy command action has effect on all the 15 internal buffer

result registers at the same time. Nonetheless, the NEW_RESULT flag is handled for each result individually, as

the SPI readout operation is individual for each line.

Table 25. Copy CMD effect

SPI readout

New measurement

data available

Copy command effect

No readout

Overwrite SPI register with buffer content (same data)

NEW_RESULT flag set

L9966

Sequencer

DS12459 - Rev 10

page 41/122

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